The invention concerns an oil filter assembly having a receiving chamber that can be closed by a cover element, and a supporting tube that is fixed in the receiving chamber and is spring-loaded for receiving a filter element through which oil can flow in a radial direction, wherein the supporting tube is displaceably disposed in the axial direction between an operating position and a drain position such that, in the operating position, in which the cover element closes the receiving chamber, it closes a drain opening, and in the drain position, when the receiving chamber is opened, it opens a drain opening. In an oil filter assembly of this type, the supporting tube is fixed to the receiving chamber in such a fashion that it remains in the housing when the filter element is exchanged. The receiving chamber can thereby be closed by the cover element e.g. by screwing on the cover element, or by swinging or latching it onto the receiving chamber. A spring element may, in particular, be provided to spring-load the supporting tube towards the drain position. The spring element may thereby be supported directly on the supporting tube and also on a housing that forms the receiving chamber.
WO01/17657 A2 (=EP1137470 A2) discloses an oil filter assembly, in which a drain dome is disposed together with a filter insert between a first position in which a drain line is closed, and a second position in which the drain line is opened, such that they can be axially moved, wherein the drain dome is fixed to the filter housing and is urged into its open position by the force of a spring. The drain dome is thereby moved against the action of the spring into its closed position by means of the filter insert that is inserted into the filter housing.
EP 1 106 795 A1 (=DE 600 18 360 T2) discloses a fluid filter having a closing element that is suited to enter into a drain channel when a cover of the filter insert closes the receiving chamber, thereby closing the channel. However, the closing element opens the drain channel when the filter insert is removed from the receiving chamber. A stop is provided on the filter insert, which cooperates with the closing element to keep it in the operating position when the cover element is closed in order to retain the closing element in the operating position. In both, WO01/17657 A2 and EP 1 106 795 A1, the filter element must disadvantageously have a certain inherent rigidity in order to keep the drain dome or the closing element in the operating position against the spring load.
It is the underlying purpose of the present invention to further develop an oil filter assembly of the above-mentioned type and thereby eliminate the disadvantages of prior art devices. In particular, an oil filter assembly is to be provided, which can be reliably operated and facilitates exchange of the filter element. The construction of the filter element itself should thereby be as simple as possible.